Two UM Researchers Had a Hand in Designing Instruments Used By NASA

As our sun rumbles around the galactic core at 486,000 mph – taking us along for the ride – it constantly emits particles called the solar wind. At the edge of the solar system, 100 times farther out than the distance between the sun and the Earth, this wind dies down as it hits the hydrogen and helium gas between stars. Interstellar space, it seems, is not totally empty.

This edge region, the interstellar boundary, forms a vast teardrop-shaped bow shock around our solar system as the sun moves along its orbital path. It’s not unlike a rock in a stream. Though astronomers have photographed the bow shocks around other stars, we know precious little about our own.

That may change Sunday, Oct. 19, with the launch of a NASA spacecraft called IBEX, the Interstellar Boundary Explorer. University of Montana scientist Dan Reisenfeld helped design one of two primary instruments on IBEX, which will create an all-sky map of the interstellar boundary.

Both Reisenfeld and fellow UM researcher Paul Janzen are part of the core payload team for the spacecraft.

“It’s been fast and furious,” Reisenfeld said of the three years between project approval and launch. “It’s exciting IBEX is ready to take off and get to work.”

The two primary instruments on the 5-foot-wide spacecraft – IBEX-Low and IBEX-Hi – detect a range of energetic neutral atoms that are energized at the boundary of the solar system. Reisenfeld designed a section of IBEX-Hi that ionizes, steers and accelerates the particles to where they can be detected.

“Dr. Janzen and I have also been very much involved with the details of how the instrument will be operated once it’s in orbit,” he said. “In addition, we have been planning how the data is going to be binned and sorted out and sent down to the ground, as well as the sequences of commands that are used to turn on and operate the instrument.”

Reisenfeld came to UM in 2004, remaining heavily involved with NASA projects while teaching Montana students courses such as Modern Physics and Quantum Mechanics. He intends to watch the launch of IBEX at the Virginia headquarters of Orbital Sciences, the private contractor that designed the rocket that will carry the probe aloft.